Skim gate



S. ZODA SKIM GATE Jan. 3l, 1928.

Filed April 14, 1926 ltatentcd dan. lil,

1,657,952 OFFICE.

SALVATDRE ZODA, OF TREN'ON, NEVI JERSEY.

llllzif GATE,

Application le. April lll, 1926.

This invention relates to skim-gates for casting molds, and has for its object the construction of novel means of the class describedfor separating the dross or slag from the molten metal as it is poured into the mol`d,in a manner more efficient and com-- plete than has hitherto been accomplished with devices designed for this purpose.

`More specifically, the objectof the invention is to provide a multipart shim-gate which when assembled forms upper and lower chambers, in the former of which the grosser slag collects, while the lower chamber functions to collect and separate from the molten metal the finer order of slag or dross which may pass through the perforated skimming plate.

The invention has for its further object the provision as part of the skim-gate, of an offset receiving hopper into the remote end of which the metal may be poured from the ladle, the sameflowing laterally through the in-gate passage instead of dropping into it from a height as in ordinary practice, thereby avoiding forcing the dross down wardly through the body of metal in the skim-gate by sheer velocity of the inflow.

Other objects of the invention will appear as the following description of a preferred embodiment thereof proceeds.

ln the drawings Fig.' 1 is a verticalsection through a two part mold and the skim-gate associated therewith, said skim-gate embodying the principles of the present invention.

Figs. 2, 3 and 4 show consecutively, perspective views of the upper, intermediate and lower members of the skim-gate.

Fig. 5 is a section taken along theline 5 5 of Fig. 1.

Referring now in detail to the several figures, the numerals 1 and 2 represent respectively `the cope and drag, together forming a twopart mold, filled with moldei"s sand in the usual manner, having the unfilled space S3 into which `the metal is to be run to form the casting. The sand in the `drag is formed with a lateral passage a communicating with the space 3 and with the skim-gate. rIhe latter consists essentially of three parts arranged in a vertical. tier embedded in the sand of the cope, and preferably a fourth part, the receivinghopper 6 which y,rests upon the surface of the sand within the cope and communicates with the inf-gate passing Serial No. lZJll.

fllhe three embedded parts include the skimming tray 7 having a peripheral flange and dished center, the latter being formed with perforations 8, preferably cylindrical. Beneath the skimming-'tray is the frustoconical well 9 having the upper edge thereof registrable with the flange of the skimming tray and converging downwardly, terminating in a relatively small outlet aperture 10. Above the skimming tray and also registrable with the peripheral flange thereof is the dome 11 having a frusto-conical chamber 12 the walls of which converge upwardly, terminating in a passage 13 which opens in the upper face of the dome and is adapted to communicate with the in-gate passage 5 of the hopper.

rlhese parts are shown in assembled relation in Fig. 1, in which it will beobserved that the hopper 6 is offset with respect to the in-gate passage, it being the intent of the invention that the metal shall be poured into the in-gate passage. It is obvious that the hopper can be oriented in any `direction to suit the convenience of the operator.

The metal flowing through the in-gate passage 5 and passage 13 collects in the dome Afaster than it can pass through the perforations 8, forming a body of molten metal in the dome chamber from which the dross or slag separates, floating to the surface of the metal and lying upon it in a layer of greater or less thickness according to circumstances.` Since the metal flows into the ing acquired a head as would be the case were it dropped from a height directly into y the in-gate passage from the ladle, the dross or slag will not be driven downwardly into the body of molten metal in the dome chamber but will rise to the surface with very little opposition from the inflow of metal. The overhanging wall of the dome chamber forms an annular space of minimum turbulence around the current of descending metal, giving the dross or slag a chance to rise wit-hout being re-eiitrained with the descending metal. Most of this slag collects upon the wall of the dome chamber and is discarded, with the dome 9 after the casting has been made.

The aggregate area. of the apertures in the skimming trav is so related to the outlet aperture 10 of the well chamber that metal flowing through the shimminfr' tray backs npin the well 9 forming a of :hielten lll) metal 4with a :space above it and below the skimming plate into which dross or slag of the liner order collects. The upwardly divergent wall ot the well chamber terms an annular space of minimum turbulence around the perforated area ot the skimming tray, in which a portion ot the slag which may pass through the tray freely acoumu-` lates; adhering` to the wall oit the well so that it, too, may be thrown away when the well is discarded.

The chamber 1:2 Vwith the upwardly converging' walls, as heretofore explained, serves to retain the greater portion ot the slag` and other impurities, and very little of the slag passes through the tray 7 into the well or Vlower chamber 9 which converges downwardly7 the latter chamber distinctively serving` to break up the pockets or balls ot gas that pass through the said tray 7 with the molten metal, so that when the latter metal passes through the outlet aperture l0 it is practically clean or tree ot slagl or dirt accumulations and gas and passes into the mold cavity or space 3 by way ot the passage 4 in a practically clean or puried condition.' and as a consequence a much better quality of castingP results in finally treating castings to render them lit for service. rlhe invention is not in the least limited to the use of the hopper G, as any inlet means may be employed in communication with the inlet passage or opening 13. lVhen the molten ,m tal is admitted through the inlet passage 123 into the conical chamber l2 it assumes a n-*hirling` motion Aand thereby forces the slag and other impurities outwardly towards the wall or" said chamber l2, and when the charge of metal thus admitted passes through the tray 7 it continues to have a whirling motion in the chamber of the well ror lower chamber 9, which is converged towards the bottom outlet opening or aperture l0, said movement of the molten metal in the well or lower chamber 5) i'orcinp,v the gases outwardly towards the wall of the said lower chamber together with a comparatively small portion oi the slag; that may pass through the tray 7, and as a consequence the metal flowing into the passage Lil; is practically free of slag: and other dirty accumulations and gas. with the result that the casing termed in the space or cavity 2l is pure and has a, homogeneity ol texture.

lt is contemplated that the several parts of my improved sliinrp'ute shall be made of molders sand baked in the usual manner and that they may be discarded alter having been used once.

lVhile I have in the above description defined what l believe to be a. practical and preferred form ot my inventionv` yet it is to be understood that the specific details in which the invention is disclosed are not limitat/ive in. their effect upon the invention. but merely by way et exemple. except where they are prescribed by the express terms ol' the appended claim.

Having' described my invention what I claim as new and desire to secure by Letters Patent, iszil shim-gate tor casting molds comprising; an upper member havingl a conical chainber provided in its top with a central inlet. a lower member having an inverted conical chamber provided in its` bottom with a eentrai outlet. both upper and lower chambers beine' otherwise imper'inate. and an interi mediate perforate tray having` au upper concave side and a lower convex side and closely fitting' between said upper and lower members.

ln testin'iony whereof l have hereunto set my hand.

SLVUlOll lil ZO DA 

